In general, electron emission displays use either hot cathodes or cold cathodes as electron sources. Electron emission displays using cold cathodes may be classified into field emitter array (FEA) types, surface conduction emitter (SCE) types, metal-insulator-metal (MIM) types, metal-insulator-semiconductor (MIS) types, ballistic electron surface emitting (BSE) types, and the like.
Electron emission devices are used to form electron emission displays, various backlights, electron beam apparatuses for lithography, and the like. A typical electron emission display comprises an electron emission substrate or first substrate, and an image forming substrate or second substrate. The electron emission substrate comprises a plurality of electron emission devices and control electrodes for controlling electron emission. The image forming substrate comprises fluorescent layers with which emitted electrons collide, thereby emitting light. The image forming substrate also comprises an electrode electrically connected to the fluorescent layers.
To improve brightness of the electron emission display, a reflective metal layer is positioned on the fluorescent layers. The metal layer directs the emitted electrons to the image forming substrate and attracts the electrons back to the fluorescent layer after they have been reflected toward the electron emission substrate by virtue of their collision with the fluorescent layers. Moreover, the metal layer prevents the remaining electrons from colliding with the fluorescent layers. Therefore, the metal layer can increase the life of the fluorescent layers and can prevent arc between the electron emission substrate and the image forming substrate. An exemplary method of fabricating such a metal layer for an electron emission display is disclosed in Korean Patent Laid-open Publication No. 2001-75972.
A method of fabricating a metal layer according to the prior art will now be described in conjunction with the accompanying drawings. FIGS. 1A through 1E are cross-sectional views of an image forming substrate according to the prior art. FIGS. 1A through 1E illustrate various steps in a prior art process for fabricating a metal layer for an electron emission display.
As shown in FIG. 1A, a metal layer is fabricated by first preparing a top layer 110. An anode electrode 120 is then formed on the top layer 110, and fluorescent layers 130 are formed on the anode electrode 120. Generally, the fluorescent layers 130 are formed in a matrix or striped pattern.
As shown in FIG. 1B, light-shielding layers 140 are formed on the anode electrode 120 in the spaces between the fluorescent layers 130. As shown in FIG. 1C, intermediate layers 150 are then formed on the fluorescent layers 130 by applying an acryl emulsion or lacquer solution to the fluorescent layers 130 and drying the solution. A metal layer 160 is then formed on the anode electrode 120, covering the intermediate layers 150, as shown in FIG. 1D. The intermediate layers 150 prevent irregular deposition of the metal layer 160 which can occur when the metal layer 160 is directly deposited on the rough surfaces of the fluorescent layers 130. By preventing uneven deposition of the metal layer 160 on the fluorescent layers 130, the intermediate layers 150 improve the reflection efficiency of the fluorescent layers 130.
Typically, the intermediate layers 150 each have a thickness of about 10 μm, and the intermediate layers 150 are removed after deposition of the metal layer 160. As a result, spaces are formed between the fluorescent layers 130 and the metal layer 160, as shown in FIG. 1E.
However, when the intermediate layers comprise an acryl component, it is difficult to adjust the spaces created between the fluorescent layers and the metal layer after removal of the intermediate layers. Moreover, these spaces between the fluorescent layers and the metal layer may cause arc on the metal layer when high exterior voltages are applied.